1. Field of the Invention
The present invention relates to a centering mechanism that performs centering of an inner casing in a turbine or a blade ring in a rotary machine such as a compressor or a turbine.
This application is based on Japanese Patent Application, Publication No. 2008-115720, the content of which is incorporated herein by reference.
2. Description of Related Art
Centering of an inner casing in a turbine or a blade ring in a rotary machine such as a compressor or a turbine is conventionally performed with the use of a pin in the horizontal direction and a key (liner) in the vertical direction (see Japanese Unexamined Patent Application, Publication No. 2005-171783 (FIGS. 2 and 3), for example).
In this case, for centering in the vertical direction, a key having a thickness larger than a planned value is made in advance, and is cut down to reduce the thickness to fit the actual inner casing or blade ring at the time of assembly and adjustment. The inner casing and the blade ring need to be adjusted such that gaps produced between moving blades and fins during operation are prevented, as much as possible, from being nonuniform in the circumferential direction, while the deformation of the casing and a bearing stand and the deflection of a rotor caused by its weight are taken into account.
However, after testing, when the deformation of the casing and the bearing stand and the deflection of the rotor caused by its weight are different from those predicted, the centering of the inner casing and the blade ring in the vertical direction and in the width direction needs to be readjusted. However, the frequency of readjusting the positions of the inner casing and the blade ring in the width direction is relatively low. Therefore, the centering in the vertical direction is mainly performed as readjustment work.
In such a case, there has been a problem in that it is necessary to make a key having a new size and to change to it, thereby taking a long time for the centering of the inner casing and the blade ring, and increasing the cost.